One- and Two-Color Resonant Photoionization Spectroscopy of Chromium-Doped Helium Nanodroplets

Markus Koch*, Andreas Kautsch, Florian Lackner, Wolfgang Ernst*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We investigate the photoinduced relaxation dynamics of Cr atoms embedded into superfluid helium nanodroplets. One- and two-color resonant two-photon ionization (1CR2PI and 2CR2PI, respectively) are applied to study the two strong ground state transitions z7P2,3,4° ← a7S3 and y7P2,3,4° ← a7S3. Upon photoexcitation, Cr* atoms are ejected from the droplet in various excited states, as well as paired with helium atoms as Cr*–Hen exciplexes. For the y7P2,3,4° intermediate state, comparison of the two methods reveals that energetically lower states than previously identified are also populated. With 1CR2PI we find that the population of ejected z5P3° states is reduced for increasing droplet size, indicating that population is transferred preferentially to lower states during longer interaction with the droplet. In the 2CR2PI spectra we find evidence for generation of bare Cr atoms in their septet ground state (a7S3) and metastable quintet state (a5S2), which we attribute to a photoinduced fast excitation–relaxation cycle mediated by the droplet. A fraction of Cr atoms in these ground and metastable states is attached to helium atoms, as indicated by blue wings next to bare atom spectral lines. These relaxation channels provide new insight into the interaction of excited transition metal atoms with helium nanodroplets.
Original languageEnglish
Pages (from-to)8373-8379
JournalThe Journal of Physical Chemistry A
Volume118
Issue number37
DOIs
Publication statusPublished - 2014

Fields of Expertise

  • Advanced Materials Science

Treatment code (Nähere Zuordnung)

  • Basic - Fundamental (Grundlagenforschung)
  • Application
  • Experimental

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